[amsat-bb] Re: I just curious

Tony Langdon vk3jed at gmail.com
Sun Jul 5 16:48:11 PDT 2009

At 05:06 AM 7/6/2009, kd8bxp at aol.com wrote:

>On the FM birds how come the split is V/U or U/V?  Are there any V/V birds?


>I know there is a reason, so I am curious that is all!

Yes, there is a reason.  V/V would make the satellite work much like 
a terrestrial repeater.  Terrestrial repeaters on 2m require bulky, 
heavy cavities, which are impractical to launch on a 
satellite.  There's also the issue of possible detuning, due to the 
vibration of launch and thermal cycling while in space.

One way a V/V satellite _could_ be made to work is to have separate 
receiver and transmitter satellites joined by a tether.  A very low 
powered link on another band could pass the signal between the 2 
sats, just as is done for some terrestrial repeaters.

However, this configuration is also more expensive to launch, and any 
in band birds take away one of the big advantages of working 
crossband - being able to hear your own downlink, and monitor the 
channel while transmitting.

73 de VK3JED / VK3IRL

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